Multiplication by 11 is simple. For a 2-digit number just add the two digits of the number multiplied by 11 and place the sum in between that number carrying any ones overs.
19 x 11
1 + 9 = 10 (you will carry the 1 )
take the first number (19) and spread out the 1 and 9
1 ____ 9
put the sum in the middle using only the last digit. Carry the ones, if any over.
1 9
1 0
-----------
2 0 9
Answer: 209
Easy. No calculator needed!